Device for supporting a conveyor belt used in the continuously operated sintering of a material bed

ABSTRACT

The invention relates to a device for supporting a conveyor belt used in the continuously operated thermal treatment, i.e. sintering, of a material bed. According to the invention, in the top part of the frame structure of the belt conveyor, there is installed at least one support element, whereby an essentially smooth slide surface can be obtained for the conveyor belt, and in the interior of the support element there is made a channel system in order to enable the flow-through of the intermediate agent fed into the support element.

The present invention relates to a device for supporting a conveyor beltused in the continuously operated thermal treatment of a material bed,i.e. in sintering, and also to improving the motional properties of thebelt.

In continuously operated sintering, there is nowadays generally used aconveyor-type sintering device, where on the conveyor belt, there isfirst formed a material bed. The material bed usually consists ofspherical, fragile pellets, which by means of a high-temperaturetreatment, i.e. sintering, are hardened so that the pellets can be fedto further treatment, for instance to a smelting furnace. In thesintering of a material bed, through the material bed located on theconveyor belt, and simultaneously through the conveyor belt itself,there is first conducted hot gas, so that the temperature of thematerial bed rises, for instance in the case of ferroalloy pellets, upto the range of 1300-1600° C. At a high temperature, the fragile pelletsreact with the hot gas and are hardened in the process. Thereafter thehardened pellets obtained in the material bed are cooled by conductingcooling gas through the material bed and the conveyor belt. Thus theconveyor belt employed in continuously operated sintering is used underremarkable fluctuations of temperature.

In order to reduce the powerful temperature changes directed to theconveyor belt, the conveyor belt is supported, at least in the part fortransporting the material bed, by a support structure which can becooled and which also serves as the slide surface for the conveyor belt.Normally the employed support structure is an arrangement where the gasused in the cooling process is fed in through the slide surface formedon top of the support bar and the support structure, meets the conveyorbelt and is exhausted along the rest of the process gases, which as suchforms a strain for the exhaust gas blasters and gas cleaning equipment.At the same time, this reduces the amount of gas flowing through thematerial bed to be sintered, which results in a poorer quality ofpellets and in a reduced capacity of the sintering device. Anotherproblem is that the exact spot where the cooling gas is exhausted hasnot been known, because particularly a worn conveyor belt begins toblister and is not at all spots evenly attached to the slide surfaceprovided on the top surface of the supporting structure. Consequentlythe cooling gas is exhausted at spots where the resistance is lowest andleaves the rest of the support structure and slide surface uncooled.

The object of the present invention is to alleviate the drawbacks of theprior art and to realize an improved device for supporting the conveyorbelt employed in the continuously operated thermal treatment, i.e.sintering, of a material bed, in which device the support structure ofthe conveyor belt comprises at least one support element that is easilyinstalled and removed, and in which device the cooling gasadvantageously circulates throughout the whole support structure. Theessential novel features of the invention are apparent from the appendedclaims.

According to the invention, the support element used for supporting aconveyor belt employed in the continuously operated thermal treatment,i.e. sintering, of a material bed, comprises two end parts and at leasttwo, mutually parallel supporting parts that are spaced apart andconnected to said end end parts. The supporting parts are parallel andspaced apart in order to enable an essentially unobstructed passage ofthe process gases, used in the thermal treatment, i.e. sintering, of thematerial bed, to the conveyor belt and further through the aperturesprovided in the conveyor belt. Thus, in aligning the supporting partswith respect to the conveyor belt, the structure of the conveyor belt istaken into account.

The support and end parts of the support element are made to becavernous, so that the cooling agent used in the cooling process can beconducted as a flow-through via the cavities. Moreover, the supportelement is provided with at least one adjusting member in order toensure an essentially accurate alignment when assembling the supportelement. Further, at least one pair of wheels is advantageously attachedto the support element in order to facilitate the replacement of thesupport element, for instance so that one wheel is provided at each endpart.

Depending on the length of the conveyor belt employed in thecontinuously operated thermal treatment, i.e. sintering, of a materialbed, one or several support elements according to the invention are usedfor supporting the conveyor belt. From the point of view of thecontinuously operated thermal treatment, i.e. sintering, of the materialbed, it is preferable that in the various process steps, where thetemperature may fluctuate within a wide range, there are used separatesupport elements. When using two or more support elements, the end partsof two successive support elements are in the operational positioninstalled adjacently to each other. In that case the end parts of thesupport element are placed transversally with respect to the proceedingdirection of the conveyor belt. The supporting parts connecting the endparts are advantageously connected to the end parts at essentially rightangles, in which case the supporting parts are in the operating positionessentially parallel to the proceeding direction of the conveyor belt.

According to the invention, in the end part of the support element ofthe conveyor belt employed in the continuously operated thermaltreatment, i.e. sintering, of a material bed, there also is formed aconnecting part for feeding cooling agent to the support element and forconducting cooling agent out of the support element. The end parts andthe supporting parts connected to the end parts are cavernous, in whichcase the cooling agent is made to pass as a flow-through through thesupport element, advantageously as separate from the rest of the processgases used in the thermal treatment, i.e. sintering, of the materialbed. When using two or more support elements, the support elements canbe combined, in relation to the cooling agent, so that one and the samecooling agent is made to flow through all elements. When using two ormore support elements, the support elements can also be connected, inrelation to the cooling agent, so that each support element functions asa separate unit, or for example so, that two successive support elementsare connected to each other, while the same amount of cooling agentpasses through both support elements. Advantageously the employedcooling agent is gas, such as air.

When necessary, the channel system formed by the support elementcavities can also be used so that instead of the cooling agent, forinstance a heating agent, such as heated air, is fed into the supportelement, for example in a case where the equipment used in the thermaltreatment, i.e. sintering, of a material bed is not in use, and theweather conditions are such that heating is required.

In order to align the support element according to the invention in adesired position with respect to the conveyor belt, in order to preventany bending of the conveyor belt, the support element is provided with aleast one adjusting member by which the height of the support elementis, during installation, advantageously adjusted with respect to theconveyor belt and the rest of the support elements. The heightdifference between a support element and the rest of the supportelements, achieved by means of the adjusting member, is advantageouslyless than 0.5 mm, in which case the support for the conveyor belt ismade essentially uniform throughout the whole supported area of theconveyor belt. Thus the conveyor belt is advantageously made to slidealong an essentially uniform slide surface formed of the top surface ofthe end parts and supporting parts of the support element, which as suchreduces the damages caused by the high temperature in the conveyor belt.The sliding of the conveyor belt can be further enhanced by feeding ontothe slide surface a lubricating agent, and the heating of said agent islikewise restricted by means of the cooling agent conducted through thesupport element.

The invention is explained in more detail with reference to the appendeddrawings, where

FIG. 1 shows a preferred embodiment of the invention in a schematicalside-view illustration,

FIG. 2 shows the preferred embodiment of FIG. 1 in a schematicaltop-view illustration, and

FIG. 3 illustrates the preferred embodiment of FIG. 1 as installed in acontinuously operated sintering arrangement.

In FIGS. 1 and 2, the end parts 2 of the support element 1 areinterconnected by supporting parts 3. In the end part 2, there isinstalled a conduit member 4 in order to feed cooling or heating agentinto the support element 1, and a conduit member 5 in order to conductcooling or heating agent out of the support element 1. The end parts 2and the supporting parts 3 are hollow, so that inside the supportelement 1, there is formed a channel system 8, where the cooling orheating agent can be conducted from the inlet conduit member 4 to theoutlet conduit member 5. In addition, the end part 2 is provided with anadjusting screw 7, whereby the height of the support element 1 can beadjusted to be advantageous with respect to the rest of the supportelements and the conveyor belt.

In FIG. 3, the conveyor belt 11 is installed on a belt conveyor 14comprising a drawing drum 12 and a folding drum 13, so that the conveyorbelt 11 transports the material bed 15 located on the belt through thesintering arrangement 16. In order to support the conveyor belt 11, inthe top part of the frame structure 17 of the conveyor 14, there areinstalled support elements 18 according to the invention, which elementsalso provide an essentially smooth slide surface for the conveyor belt11.

What is claimed is:
 1. A belt conveyor for use in continuous thermaltreatment of a material bed, comprising a conveyor belt having anelongate upper run and also comprising a frame structure for supportingthe upper run of the conveyor belt, wherein the frame structure includesat least one hollow support element defining an interior space, thesupport element comprises two end members that extend lengthwise of theupper run of the conveyor belt at opposite respective edges of the upperrun and at least two transverse members that are mutually parallel andare spaced lengthwise of the upper run of the conveyor belt, the supportelement has an inlet opening and an outlet opening for enabling a flowof heat-transfer fluid through the interior space of the supportelement, and the interior space of the support element is otherwisesubstantially isolated from the exterior of the frame structure.
 2. Abelt conveyor according to claim 1, wherein the two end members and thetransverse members are hollow and each defines an interior space, andthe interior spaces of the end members and the transverse members are incommunication with each other.
 3. A belt conveyor according to claim 1,wherein the support element includes an adjusting member for selectivelyadjusting the height of the support element.
 4. A belt conveyoraccording to claim 1, wherein the end members are connected by thetransverse members and the transverse members are perpendicular to theend members for supporting the upper run of the conveyor belt.
 5. A beltconveyor according to claim 1, wherein the end members and thetransverse members have respective top surfaces that form an essentiallyuniform slide surface for the upper run of the conveyor belt.
 6. A beltconveyor according to claim 1, wherein said hollow support element is afirst of at least first and second hollow support elements each havingan inlet opening and an outlet opening and wherein the outlet opening ofthe first support element is connected to the inlet opening of thesecond support element so that the heat transfer fluid passessuccessively through the interior spaces of the first and second supportelements.
 7. A belt conveyor according to claim 1, wherein said hollowsupport element is a first of at least first and second support elementsand each support element is provided with at least one adjusting memberfor selectively adjusting the support element in height.
 8. A beltconveyor for use in continuous thermal treatment of a material bed,comprising a conveyor belt and a frame structure for supporting an upperrun of the conveyor belt, wherein the frame structure includes at leastone hollow support element defining an interior space, the supportelement has an inlet opening and an outlet opening for enabling a flowof heat-transfer fluid through the interior space of the supportelement, and the interior space of the support element is substantiallyisolated from the ambient atmosphere.
 9. A belt conveyor according toclaim 8, wherein the support element includes an adjusting member forselectively adjusting the height of the support element.
 10. A beltconveyor according to claim 8, wherein the support element has a topsurface that forms an essentially uniform sues surface for the upper runof the conveyor belt.
 11. A belt conveyor according to claim 8, whereinsaid hollow support element is a first of at least first and secondhollow support elements each having an inlet opening and an outletopening and wherein the outlet opening of the first support element isconnected to the inlet opening of the second support element so that theheat transfer fluid passes successively through the interior spaces ofthe first and second support elements.
 12. A belt conveyor according toclaim 8, wherein said hollow support element is a first of at leastfirst and second support elements and each support element is providedwith at least one adjusting member for selectively adjusting the supportelement in height.